<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>基本选择器</title>
    <style>
        /*元素选择器*/
        div{
            color: red;
        }

        /*类选择器*/
        .cls{
            color: blue;
        }

        /*id选择器*/
        #d1{
            color: green;
        }
        #d2{
            color: pink;
        }
    </style>
</head>
<body>
    <div>div1</div>

    <div class="cls">div2</div>
    <div class="cls">div3</div>

    <div id="d1">div4</div>
    <div id="d2">div5</div>
</body>
</html>